Method for manufacturing machining tool

ABSTRACT

A method of manufacturing a machining tool in which an insert holder comprises a first surface, a second surface opposite the first surface, and a first insert tip slot extending between the first surface and the second surface. The first insert tip slot is configured so as to be compressed and densified to support a first insert tip. The insert holder further includes elevated projections extending from the first and second surfaces proximate the first insert tip slot.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional application of U.S. patent application Ser. No.13/515,157, filed Jun. 11, 2012, which represents the national stageentry of PCT International Application No. PCT/US2011/020342 filed Jan.6, 2011, which claims the benefit of U.S. Provisional Patent ApplicationNo. 61/292,933, filed Jan. 7, 2010, the disclosures of which are herebyincorporated by reference for all purposes.

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

This invention relates to cutting tools, particularly a cutting tool inwhich a cutting insert tip is supported by an insert holder.

Machining tools, such as milling, drilling, and cutting tools, typicallyinclude a cutting insert tip comprising materials such as ceramics,nitrides, carbides, aluminum oxides, iron oxides, natural or syntheticdiamond, or the like. To reduce the overall cost of the tool, the inserttip is supported by an insert holder comprising a less expensivematerial, such as tool steel or the like.

Previous machining tools have used several methods to provide sufficientholding forces between insert holders and insert tips to resist cuttingforces experienced during machining processes. For example, in somecases insert tips are connected to insert holders via brazing.Unfortunately, brazing dissimilar materials can be relatively difficultand therefore expensive.

As another example, in some cases insert tips are connected to insertholders via press fitting. Unfortunately, press fitting requires inserttips and insert holders having relatively small tolerances (e.g., on theorder of a few ten-thousandths of an inch) in order to ensureappropriate engagement between the components. Of course, insert tipsand insert holders having such tolerances are relatively expensive.

Considering the drawbacks of previous designs, relatively inexpensivemachining tools and methods for manufacturing such machining tools areneeded.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a method of manufacturinga machining tool with an insert holder that comprises a first surface, asecond surface opposite the first surface, and a first insert tip slotextending between the first surface and the second surface. The firstinsert tip slot is configured to support a first insert tip. The insertholder further comprises a first elevated projection extending from thefirst surface proximate the first insert tip slot.

In another aspect, the present invention provides a method ofmanufacturing a machining tool comprising an insert holder having aninsert holder hardness. The insert holder includes a first portionhaving a first density and a second portion integrally connected to thefirst portion. The second portion defines a first insert tip slot andhas a second density. The second density is greater than the firstdensity. The machining tool further comprises a first insert tipsupported in the first insert tip slot by the second portion. The firstinsert tip has a first insert tip hardness, and the first insert tiphardness is greater than the insert holder hardness.

In yet another aspect, the present invention provides a method ofmanufacturing a machining tool, comprising the steps of 1) providing aninsert holder having a first insert tip slot; 2) positioning a firstcutting insert tip within the first insert tip slot; and 3) compressingthe insert holder to thereby secure the first cutting insert tip withinthe first insert tip slot.

These aspects and advantages of the invention will be apparent from thedetailed description and drawings. What follows is merely a descriptionof some preferred embodiments of the present invention. To assess thefull scope of the invention the claims should be looked to as thesepreferred embodiments are not intended to be the only embodiments withinthe scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will hereafter be described with reference to theaccompanying drawings, wherein like reference numerals denote likeelements, and:

FIG. 1 is a perspective view of a machining tool according to thepresent invention after securing cutting insert tips to an insert holderof the tool;

FIG. 2 is a top view of the machining tool of FIG. 1;

FIG. 3 is a perspective view of the insert holder of the machining toolof FIG. 1 before securing the cutting insert tips to the insert holder;

FIG. 4 is a top view of the insert holder of FIG. 3;

FIG. 5 is a front view of the insert holder of FIG. 3;

FIG. 6 is a sectional view of the insert holder along line 6-6 of FIG.5;

FIG. 7 is a flow chart of a method of manufacturing the machining toolof FIG. 1;

FIG. 8 is a perspective view of a second embodiment of a machining toolaccording to the present invention after securing cutting insert tips toan insert holder of the tool;

FIG. 9 is a top view of the second embodiment of the machining tool ofFIG. 8;

FIG. 10 is a perspective view of the insert holder of the secondembodiment of the machining tool of FIG. 8 before securing the cuttinginsert tips to the insert holder;

FIG. 11 is a top view of the insert holder of FIG. 10;

FIG. 12 is a front view of the insert holder of FIG. 10; and

FIG. 13 is a sectional view of the insert holder along line 13-13 ofFIG. 12.

DETAILED DESCRIPTION OF THE DRAWINGS

The particulars shown herein are by way of example and only for purposesof illustrative discussion of the embodiments of the invention. Theparticulars shown herein are presented to provide what is believed to bethe most useful and readily understood description of the principles andconceptual aspects of the invention. In this regard, no attempt is madeto show structural details of the invention in more detail than isnecessary for the fundamental understanding of the invention. Thedescription taken with the drawings should make apparent to thoseskilled in the art how the several forms of the present invention may beembodied in practice.

Referring now to the drawings and particularly FIGS. 1-6, a machiningtool 10 according to the present invention includes an insert holder 12that supports first and second cutting insert tips 14 and 16 on oppositesides. The insert tips 14 and 16 are secured by deforming severalelevated projections 54 and 56 (FIG. 3) on the insert holder 12 duringmanufacturing. These aspects of the machining tool 10 are described infurther detail in the following paragraphs, beginning with the inserttips 14 and 16 and concluding with methods for manufacturing themachining tool 10.

The insert tips 14 and 16 engage and cut work pieces in machiningprocesses. As such, the insert tips 14 and 16 comprise a hard material,preferably cubic boron nitride, although other materials such asceramics, nitrides, carbides, aluminum oxides, iron oxides, natural orsynthetic diamond, or the like, may be used without departing from thescope of the invention. Furthermore, the insert tips 14 and 16 are alsopreferably seven-sided and have three-dimensional general spade shapesto facilitate cutting in machining processes.

The insert holder 12 comprises a material that is less hard than theinsert tips 14 and 16. Specifically, the insert holder 12 preferablycomprises a sintered powder metal, such as FN-0205 nickel steel, asdescribed in further detail below. Other materials, such as iron-nickelsteel powder metals, stainless steel powder metals, or the like, mayalso be used.

Still referring to FIGS. 1-6, the insert holder 12 includes a main bodyor first portion 18 having a density that is preferably at mostsubstantially 85 percent of the full or theoretical density of theholder material, and more preferably substantially 85 percent of thefull density of the holder material (substantially meaning +/−2.5percent). Of course, the term “full density” should be understood tomean the density of the material when it does not include any internalpores. In the present case, such internal pores are due to forming theinsert holder 12 from powder metal.

The main body 18 of the insert holder 12 preferably has a modifiedrhombus shape and is symmetric over two perpendicular planes 20 and 22(FIG. 2) that intersect in the center of the insert holder 12. Theinsert holder 12 also includes a first or upper surface 23, a second orlower surface 24 (FIGS. 5 and 6), and a center hole 25 extending betweenthe upper and lower surfaces 23 and 24. A fastener (not shown) mayextend through the center hole 25 to secure the machining tool 10 to asupport (not shown).

Referring particularly to FIGS. 2-4, the insert holder 12 also includesa first insert tip slot 26 extending between the upper and lowersurfaces 23 and 24 in which the first insert tip 14 is supported. Thefirst insert tip slot 26 is defined by three sides, i.e., two sidesurfaces 28 and one backing surface 30. The side surfaces 28 may beangled toward one another extending away from the center of the insertholder 12 to prevent the insert tip 14 from detaching from the insertholder 12 by moving in a direction perpendicular to the plane 22.

Referring now to FIGS. 1 and 2, the sides 28 and 30 of the first inserttip slot 26 are defined by a second portion 32 of the insert holder 12integrally connected to the main body 18. As used herein, the term“integral” and variations thereof describe portions of components thatare formed with adjacent portions from a single piece of material. Thesecond portion 32 includes increased-density features near both theupper and lower surfaces 23 and 24 of the insert holder 12. That is, thesecond portion 32 includes side increased-density features 34 proximateeach of the side surfaces 28 and backing increased-density features 36proximate the backing surface 30.

Each of the increased-density features 34 and 36 has a density that ispreferably at least substantially 95 percent of the holder material'sfull density, and more preferably substantially 100 percent of theholder material's full density. Such densities are provided by a swagingprocess as described in further detail below. This process also causesdeformation of the sides 28 and 30 of the first insert tip slot 26(e.g., the cross-sectional area of the slot is 26 is slightly reduced)to secure the first insert tip 14 within the first insert tip slot 26.Furthermore, the increased-density features 34 and 36 are locatedprimarily near the upper and lower surfaces and side surfaces of theinsert holder 12. That is, the increased-density features 34 and 36 donot have a uniform cross-sectional area that extends from the uppersurface to the lower surface of the insert holder 12. Similarly, in someembodiments the insert holder 12 includes a density gradient betweeneach of the increased-density features 34 and 36 and the lower-densitymain body 18 of the holder 12.

The insert holder 12 further includes a second insert tip slot 38 inwhich the second insert tip 16 is supported. The second insert tip slot38 is defined by a third portion 40 of the insert holder 12 integrallyconnected to the main body 18. The third portion 40 is generallyidentical to the second portion 32 of the insert holder 12, andtherefore is not described in detail.

Referring now to FIGS. 3-7, the machining tool 10 is preferablymanufactured as follows. First, at step 110 a base material (e.g.,FN-0205 nickel steel powder metal) is compacted in a press to form aninsert holder 12 having the shape shown in FIGS. 3-6. The insert holder12 originally includes elevated projections instead of increased-densityfeatures. That is, the insert holder 12 includes generally triangularside elevated projections 54 and generally semi-circular backingelevated projections 56. The side elevated projections 54 and thebacking elevated projections 56 preferably have heights of approximately0.50 mm and 0.25 mm, respectively, to ensure adequate material flowwhile preventing excessive compression forces in subsequent steps. Theinsert holder 12 is then sintered, e.g., at 1120 degrees C. for 30minutes at step 112.

Next or simultaneously with the previous steps, a second base material(e.g., cubic boron nitride) is wire cut to form the insert tips 14 and16 at step 114. Both the insert tips 14 and 16 and the insert tip slots26 and 38 of the insert holder 12 may be manufactured with relativelylarge tolerances (e.g., on the order of several thousandths of an inch)because press fitting is not used to secure the insert tips 14 and 16 tothe insert holder 12.

The first and second insert tips 14 and 16 are then positioned in thefirst and second insert tip slots 26 and 38, respectively, at step 116.The insert holder 12 is then compressed or swaged axially (i.e., in adirection perpendicular to the upper and lower surfaces 23 and 24) by apress at step 118. Such a compression process deforms the elevatedprojections 54 and 56 to provide the increased-density features 34 and36, respectively. This deformation secures the insert tips 14 and 16within the insert tip slots 26 and 38, respectively. The machining tool10 may be compressed within a fixture that surrounds the sides of thetool 10; such a fixture insures that the side elevated projections 54 donot deform away from the insert tips 14 and 16. Finally, the machiningtool 10 may be steam treated at step 120 to increase bonding between theinsert tips 14 and 16 and the insert holder 12 and to increase corrosionresistance of the machining tool 10.

Of course, the machining tool may be manufactured differently or havedifferently shaped features from the above description without departingfrom the scope of the invention. For example and referring now to FIGS.8-13, a second embodiment of a machining tool 210 according to thepresent invention includes an insert holder 212 that supports first andsecond insert tips 214 and 216 within first and second insert tip slots226 and 238, respectively. The machining tool 210 is generally asdescribed above, although the second and third portions 232 and 240include modified elevated projections. Specifically, the side elevatedprojections 254 and the backing elevated projections 256 (FIGS. 10-13)have general pyramid shapes and heights of approximately 0.40 mm and0.10 mm, respectively. Such elevated projections 254 and 256 providesmaller increased-density features 234 and 236 (FIGS. 8 and 9) andreduce the loading between the insert holder 212 and the insert tips 214and 216. Such reduced loading may be useful depending on the specificmaterials used for each of the components.

As another example, the insert tips 14 and 16 may be slightly shorterthan the insert holder 12. In such embodiments, the elevated projections54 and 56 may be deformed to provide small lips (not shown) at the edgesbetween the upper and lower surfaces 23 and 24 and the insert slots 26and 38 to further secure the insert tips 14 and 16.

From the above description it should be apparent that the presentinvention provides relatively inexpensive machining tools and methodsfor their manufacture. These advantageous tools and methods arefacilitated, in part, due to the relatively large tolerances of theinsert holder and the insert tips and using the relatively simpleprocess of compressing the elevated projections to secure the inserttips in the insert holder.

It should be appreciated that various other modifications and variationsto the preferred embodiments can be made within the spirit and scope ofthe invention. Therefore, the invention should not be limited to thedescribed embodiments. To ascertain the full scope of the invention, thefollowing claims should be referenced.

What is claimed is:
 1. A method of manufacturing a machining tool,comprising the steps of: providing an insert holder having a firstinsert tip slot; positioning a first cutting insert tip within the firstinsert tip slot; and compressing the insert holder to thereby secure thefirst cutting insert tip within the first insert tip slot.
 2. The methodof claim 1, wherein the step of providing the insert holder includesproviding at least a first elevated projection proximate the firstinsert tip slot, and wherein the step of compressing the insert holderincludes compressing the first elevated projection to thereby deform thefirst elevated projection and secure the first cutting insert tip withinthe first insert tip slot.
 3. The method of claim 1, wherein the step ofcompressing the insert holder provides an increased-density portionproximate the first insert tip slot.
 4. The method of claim 3, whereinthe insert holder comprises a base material, the density of theincreased-density portion is substantially 100 percent of a full densityof the base material, and the density of other portions of the insertholder is substantially 85 percent of the full density of the basematerial.
 5. The method of claim 1, wherein the step of providing theinsert holder includes forming the insert holder as a powder metalcompact and sintering the powder metal compact.
 6. The method of claim1, wherein the insert holder further includes a second insert tip slot,and further comprising the steps of: positioning a second cutting inserttip within the second insert tip slot; and compressing the insert holderto thereby simultaneously secure the first cutting insert tip within thefirst insert tip slot and the second cutting insert tip within thesecond insert tip slot.
 7. A method of manufacturing a machining tool,comprising: providing a machining tool insert holder having: a firstsurface; a second surface opposite the first surface; a first insert tipslot extending between the first surface and the second surface, thefirst insert tip slot being configured to support a first cutting inserttip; and a first elevated projection of a material that is less thanfull density of the machining tool insert holder material, the firstelevated projection extending from the first surface proximate the firstinsert tip slot; positioning a first cutting insert tip in the firstinsert tip slot; and deforming the first elevated projection to increaseits density to secure the cutting insert tip in the first insert tipslot.
 8. The method of manufacturing a machining tool of claim 7,wherein the first insert tip slot is defined by two side surfacesdisposed on opposite sides of a backing surface, the first elevatedprojection being disposed proximate a first of the side surfaces, andfurther comprising: a second elevated projection extending from thefirst surface proximate the backing surface; and a third elevatedprojection extending from the first surface proximate a second of theside surfaces.
 9. The method of manufacturing a machining tool of claim8, wherein the side surfaces are angled toward one another extendingaway from a center of the insert holder.
 10. The method of manufacturinga machining tool of claim 7, wherein the first elevated projection isone of a first plurality of elevated projections extending from thefirst surface proximate the first insert tip slot, and furthercomprising a second plurality of elevated projections extending from thesecond surface proximate the first insert tip slot.
 11. The method ofmanufacturing a machining tool of claim 10, further comprising: a secondinsert tip slot extending between the first surface and the secondsurface, the second insert tip slot being configured to support a secondcutting insert tip; a third plurality of elevated projections extendingfrom the first surface proximate the second insert tip slot; and afourth plurality of elevated projections extending from the secondsurface proximate the second insert tip slot.
 12. The method ofmanufacturing a machining tool of claim 10, wherein each of the firstplurality of elevated projections has a height from the first surface ina range of 0.10 mm to 0.50 mm, and each of the second plurality ofelevated projections has a height from the second surface in a range of0.10 mm to 0.50 mm.
 13. The method of manufacturing a machining tool ofclaim 7, wherein the insert holder comprises a sintered powder metal.14. A method of manufacturing a machining tool, comprising: providing amachining tool insert holder having an insert holder hardness, theinsert holder including: a first portion having a first density; asecond portion integrally connected to the first portion, the secondportion defining a first insert tip slot, and the second portion havinga second density, the second density being greater than the firstdensity; and placing a first cutting insert tip in the first insert tipslot, the first cutting insert tip having a first cutting insert tiphardness, the first cutting insert tip hardness being greater than theinsert holder hardness; wherein the first insert tip slot is defined bythree sides, and the second portion includes: a first feature proximatea first of the three sides, the first feature having the second density;a second feature proximate a second of the three sides, the secondfeature having the second density; and a third feature proximate a thirdof the three sides, the third feature having the second density.